Jet routes extend vertically from which flight level range?

Jet routes extend vertically from which flight level range?

• A. MEA to FL180
• B. FL180 to FL450
• C. FL290 to FL450
• D. FL100 to FL400

Answer: (B)

Jet routes are high‑altitude IFR enroute airways designed for efficient, safe movement of fast, long‑range aircraft in the upper airspace. In the United States, these routes extend from flight level 180 (18,000 feet) up to flight level 450 (45,000 feet). The lower limit at FL180 keeps jet routes distinct from the lower, VOR‑based Victor airways used below that altitude, while the upper limit at FL450 provides a defined ceiling that leaves room for other upper‑level routing structures and ensures adequate separation and navigation performance for high‑altitude traffic.

Jet routes are high‑altitude IFR enroute airways designed for efficient, safe movement of fast, long‑range aircraft in the upper airspace. In the United States, these routes extend from flight level 180 (18,000 feet) up to flight level 450 (45,000 feet). The lower limit at FL180 keeps jet routes distinct from the lower, VOR‑based Victor airways used below that altitude, while the upper limit at FL450 provides a defined ceiling that leaves room for other upper‑level routing structures and ensures adequate separation and navigation performance for high‑altitude traffic.